The present invention is directed to sensors, and, more particularly, to nanoscale sensor arrays for detecting multiple different chemical and biological species.
Prior art demultiplexers are well known, as are nanoscale wire sensors. However, the detectors described in the prior art require active circuitry to measure the current flowing through each wire. This means that each semiconductor wire must have its own measurement circuitry, which is expensive, and it also severely limits the density at which detector wires can be integrated onto a sensing platform.
The prior art sensors have demonstrated high sensitivity to chemical and biological species, and are based on converting a chemical quantity into electrical signals. As one example of a well-known device, a crossed-wire device comprises two wires and an active material sandwiched therebetween. When a chemical or biological species is absorbed onto the active material, it will change the electrical properties in the device.
The active material can be a semiconductor, a dielectric material (e.g., an oxide), a polymer, a molecule, etc. The device can be a resistor, a capacitor, a diode, a transistor, etc. Such materials and devices have been described elsewhere.
The problem for such sensors is that the change of the electrical properties only rely on the interaction between the active material and the species; usually, one kind of active material is only sensitive to one or a few species, so that such a sensor can only detect one or a few species. Alternatively, such sensors may detect too many species and not be able to distinguish between them.
It would be desirable to sense a large number of species and read out the electrical signals associated with the detection of such species.